RHEUM PALMATUM. 
reddens tincture of litmus, is not altered in its transparency by 
the addition of water, and strikes a blackish olive hue with 
solution of sulphate of iron, but no immediate precipitate falls. 
Sulphuric ether takes up 1.5 in 10 parts of this rhubarb. The 
tincture is of a golden yellow hue, and when evaporated in 
water, leaves a thin pellicle of yellow resin and abundance of 
extractive dissolved in the water, combined however with tannin. 
Aceording to the analysis of M. Henry, it contains a yellow 
coloring matter, a bland oil, fecula, a small quantity of gum, 
tannin, lignine, oxalate of lime, supermalate of lime, sul- 
phate of lime, a salt of potassa, and oxide of iron. East 
India or Chinese rhubarb has a strong odor, and is more nauseous 
to the taste than the Turkey, breaks with a more compact and 
smoother fracture, and affords a powder of a redder shade. 
Water takes up thirty parts in sixty, the infusion is not so deep 
colored as that of Russian rhubarb, is more turbid, and reddens 
also litmus paper. Alcohol extracts four parts in ten. The 
tincture is of a much deeper color, and brownish, and gives a 
deeper red to litmus tincture, is rendered slightly turbid by the 
addition of water, and strikes a green, not blackish olive with 
sulphate of iron, which it also quickly and copiously precipitates. 
Ether takes up two parts in ten, the tincture is deeper colored, 
and when evaporated on water, affords the same results except 
that the compound of tannin and extractive is more soluble. 
Ruvears is a mild purgative, and may be given to the 
youngest infants. Its operation is quickened by the addition 
of neutral salts and calomel, the purgative powers of which it 
also reciprocally augments, so that a compound, formed of small 
portions of rhubarb and a neutral salt or calomel, acts with more 
certainty and quicker than large doses of either separately 
taken. Rhubarb is particularly adapted for the majority of 
cases of diarrhoea, as it evacuates any acrid matter that may 
be offending the bowels, before it acts as an astringent. Exter- 
nally it has been applied by friction to produce its purgative 
_ effects, and its powder is sometimes sprinkled over uleers to 
assist their granulation and healing. It colors the urine in the 
space of twenty minutes after it is taken, and may be detected 
by the aid of an alkali. It disappears after an hour or two, 
but re-appears owing to a second absorption from the colon. 
Bradner Staart also affirms that it can be detected in the urine 
after using a bath impregnated with it, The Chinese use it 
_ medicinally, but chiefly to color a spirituous liquor. 
